Effects of Water Temperature on Respiration in the Pearl Oyster, Pinctada fucata martensii

Abstract

In the pearl oyster, Pinctada fucata martensii, amount of oxygen uptake (Vo₂), ventilation volume (Vg), oxygen utilization (U) and gill cilia movement (SP) increased with water temperature rising at a rate of 1°C/30 min. Vo₂ showed a maximum at 27, 31 and 33°C, and U a maximum at 30, 34 and 35°C, when rising from 12 (February), 20 (May) and 27°C (September), respectively. Vg showed a maximum at a temperature 5°C higher than each of the initial one. SP showed a maximum at 30, 34 and 35°C which showed no agreement with the maximum of Vg. Vg increased when the shell valves and the mantle lobes were open in the high water temperature. The decrease of Vg was observed when the shell valves and the mantle lobes was kept on compulsorily. The results showed that the pearl oyster corresponded mainly by increasing U to the increase of metabolism as water temperature rising, and that ventilation was done by moving water through the gill cilia movement, but Vg was controlled synthetically by the size of the opening of the shell valves and the mantle lobes, and by changing the watercouse resistance in the gills.